Hongkong Post says hackers on Monday accessed its online portal EC-Ship, possibly obtaining account holder details.

It said it had now blocked the unauthorised access and that normal service had resumed.

In a late night statement, Hongkong Post said it had contacted the Police, the Office of the Privacy Commissioner for Personal Data, and the Security Bureau about the incident, which it said involved "robotic access".

Hongkong Post said hackers may have gained access to senders' and recipients' names, addresses, phone numbers, fax numbers and email addresses. The number of people affected was still being ascertained.

It said those affected would be informed, and that Hongkong Post would never send embedded hyperlinks to collect personal information or request payment.

People with questions were urged call its general enquiry hotline at 2921 2222.